8.8 billion habitable Earth-size planets exist in Milky Way alone

[napkinz]

Seth Borenstein
The Associated Press
November 5, 2013

WASHINGTON — Space is vast, but it may not be so lonely after all: A study finds the Milky Way is teeming with billions of planets that are about the size of Earth, orbit stars just like our sun, and exist in the Goldilocks zone — not too hot and not too cold for life.

Astronomers using NASA data have calculated for the first time that in our galaxy alone, there are at least 8.8 billion stars with Earth-size planets in the habitable temperature zone. The study was published Monday in the journal Proceedings of the National Academy of Sciences. For perspective, that's more Earth-like planets than there are people on Earth.

As for what it says about the odds that there is life somewhere out there, it means "just in our Milky Way galaxy alone, that's 8.8 billion throws of the biological dice," said study co-author Geoff Marcy, a longtime planet hunter from the University of California at Berkeley.

The next step, scientists say, is to look for atmospheres on these planets with powerful space telescopes that have yet to be launched. That would yield further clues to whether any of these planets do, in fact, harbor life. The findings also raise a blaring question, Marcy said: If we aren't alone, why is "there a deafening silence in our Milky Way galaxy from advanced civilizations?"

read more: http://www.nbcnews.com/science/8-8-billion-habitable-earth-size-planets-exist-milky-way-8C11529186

[enlightenment]

1. I don't think the question is "blaring"

"Glaring" maybe - it's an obvious question, but not a particularly noisy one.

And there are probably many, many very good answers to it that are a lot more scientific than my first thought, which was "why would they bother?"

[napkinz]

6. re answering the "blaring question"

It's beyond my ken.

Calling on Neil deGrasse Tyson. Or other DU members with a science background.

(I find this stuff FASCINATING!)

[JHB]

12. Either the writer was being cute, juxtaposing with "deafening silence", or...

...was just a dope sloppy with word choice.

[GreenPartyVoter]

2. Why do we assume advanced civilizations communicate with

technology we currently possess?

[napkinz]

7. are you speaking of something like television or radio signals we might pick up?

(assuming they have such technology that would transmit signals)

[GreenPartyVoter]

8. Yes. It's possible that they followed a similar path and used them at one time, but would those

signals still be out there or could they reach us here?

[napkinz]

9. Aren't we listening for signals?

And what if the signals reached us BEFORE we had the technology to pick them up?

For all we know, signals may have reached us 100 years ago, 1000 years ago ... when we lacked the technology to pick up transmissions.

(Our Maxwell Smart moment: "Missed it by that much!&quot

[GreenPartyVoter]

21. Exactly what I was thinking.

[Warpy]

26. Once you get to the edge of the solar system

you can't pick up ordinary broadcast signals at all, they're lost in the background noise from the universe as a whole. It has to be a strong, directed signal. Eventually, Og from Zorn might pick up the signals to or from Voyager if he's buzzing it to see what the hell it is, but he'll be spared "Car 54, Where Are You?"

It will be long gone.

[longship]

30. What!? No Tootie and Muldoon? That's an outrage!

There's a holdup in the Bronx.
Brooklyn's broken out in fight.
There's a traffic jam in Harlem,
That's backed up to Jackson Heights.
A scout troop's lost a child.
Khrushchev's due at Idlewild!

Car 54, where are you!

From memory, I might add.

[pokerfan]

10. I don't think anyone in SETI assumes that.

Unfortunately we can't listen for forms of communication we haven't yet discovered.

[JHB]

13. It's more of a case of us not picking up on their signals to each other...

The equivalent of their radio, television, and other electromagnetic emissions. Not even decoding them to make sens of them, just raw signal. So far nothing fits the profile of what one might look like from many light-years away.

[The Straight Story]

3. And we will never set foot on them. We will spend the money to kill each other instead

By the time we realize we need off of this rock we won't have the resources or time to do it. But the wealthy and powerful will sure have had fun while they were here at the expense of us all.

[Dreamer Tatum]

5. Yeah, between traveling at the speed of light and the F-35

We chose the F-35.

[Rex]

25. Oh come on now! We need more brand new airplanes sent

directly into the junkyard! What have you got against tremendous government waste? As you can see, some LOVE IT!

[SoCalNative]

4. Can we send all of the teabaggers

and Republicans there please?

[napkinz]

17. America's 2010 "honeymoon" with the Teabaggers is OVER!

So, in that spirit, send them "Bang! Zoom! To the moon, Alice, to the moon!"

[longship]

38. Don't forget the telephone sanitizers.

The Golgafrincham space ark.

The tea baggers will believe anything. They'll certainly go for the mutant star goat narrative.

On your way to save mankind, tea baggers!

To be sure that our destination has a proper political structure (and clean telephones) we are going to send your ark ship off first.

Bon voyage.

[snooper2]

11. Did god create those one at a time, or was one big POOF and they appeared?

I guess she/he/it engineered the gaps in time?

[napkinz]

20. Oh how I would love to hear a response from the Creation "Scientists"

[KamaAina]

14. Enough for each of us!

[MineralMan]

15. All Tea Party Members will report to their nearest space launch facility

for exploration duty. This opportunity to explore galactic planets is brought to you by Democratic Underground.

[RobertEarl]

16. Good

So we may not be killing all the life in the milky way?

I mean, we may not be the only planet that has life.

[csziggy]

18. Another number to plug into the Drake Equation

"The Drake equation is a probabilistic argument used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way galaxy."

The Drake equation is:

N = R_{\ast} \cdot f_p \cdot n_e \cdot f_{\ell} \cdot f_i \cdot f_c \cdot L

where:

N = the number of civilizations in our galaxy with which communication might be possible (i.e. which are on our current past light cone);

and

R* = the average rate of star formation in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fl = the fraction of planets that could support life that actually develop life at some point
fi = the fraction of planets with life that actually go on to develop intelligent life (civilizations)
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space
http://en.wikipedia.org/wiki/Drake_equation#The_equation

[KurtNYC]

31. But where are the communications then? we are listening and looking for life

out there but have seen none yet.

Perhaps this is more fodder for the theory (the name escapes me) that once a civilization reaches the point we are at now, highly technological and novices at space travel, it ends quickly thereafter.

[csziggy]

35. One variation assumes civilizations only use broadcast communications

That can span interstellar distances or a short time - or at least that are easily distinguishable. Or as you say, that civilizations only last for a relatively short period. There is a good amount of discussion of that possibility on the Wikipedia page and reams at other sources.

[napkinz]

41. Carl Sagan ...

[csziggy]

42. Sagan's off the cuff guestimate was way higer than the current one

For the possible number of habitable worlds.

[lumberjack_jeff]

19. There's not only a solar "goldilocks zone" but a galactic one too.

Earth is on the distant outskirts of the galaxy, and so we've been spared the sterilizing effects of nearby supernovae.

[Gravitycollapse]

23. We are only halfway down one of the spiral arms. We are not on the outskirts at all.

[exboyfil]

28. Speculation is that the solar systems movement

in and out of the galactic plane has helped the development of humans (we are somewhat out right now). It gets more dangerous as we get into a larger density of stars.

http://www.livescience.com/9199-earth-biodiversity-trace-bobbing-solar-system-path.html

I think we need to discount solar systems in the higher density of the galaxy.

Also if you consider the other factors which must come together and how much time we used up on the clock, I suspect complex life (especially technological societies) are very rare. Our species has gone through several keyhole events.

http://io9.com/5501565/extinction-events-that-almost-wiped-out-humans


http://www.astrobio.net/debate/239/odds-of-complex-life

[ecstatic]

22. "If we aren't alone, why is there a deafening silence"

I, like many people, am very fascinated by the idea of people living on other planets. But realistically speaking-- what would happen if an "advanced civilization" sent a ship or message to us (or vice versa)? I'm not sure that it would be received in a positive way.

A truly advanced civilization (with good intentions) would understand that no good would come of a random visit. If anything, they'd just watch us from a distance, not intervening unless we were at risk of an extinction level event or something.

[lumberjack_jeff]

29. Exactly. Fermi was right. n/t

[longship]

39. Ian Stewart has it right.

Ian Stewart, British mathematician, has the definitive answer to the Fermi paradox.

All planets with intelligence and technology become aware of the Fermi paradox. Maybe they are all sitting around listening and asking, "Where is everybody?"

And they're all doing it.


Kind of a Douglas Adams solution. But it works for me.

[Coyotl]

24. And not one of them would support human life because we evolved on this one.

So, let's quit fu**ing up the only option we have.

[LuvNewcastle]

34. Agreed. We don't really deserve to find other planets to inhabit

until we appreciate and care for what we have. We don't have any proof that there are other worlds for us to live in so far. I would be fascinated if we did find other planets, but we never should take Earth for granted no matter how many alternatives we might one day find.

[Nevernose]

27. Maybe I'm having a Zaphod Beeblebeox moment

But in all this discussion of more advanced life forms, no one has addressed the possibility that we are[/] the most advanced life forms in the galaxy. Statistically it's not more or less probable than being at the bottom of the stack or somewhere in the middle of the galactic hierarchy.

[KurtNYC]

32. what if civilizations get to this point and then die off quickly?

Consider that the average IQ in the western world has declined 15 points since the Victorian era and we have a trajectory to disaster. In another 100 years, we will be more immersed in the complex tech problems that we have created for ourselves and yet the average IQ will be 85.

In the 'use it or lose it' maxim of biology, the advancement of robotics, AI and other technologies mean that we, as a species, can survive with less intelligence and less physical health but that trend could easily take us to extinction.

[spanone]

33. we're just spizwinks in space...along with a gazillion more spizwinks.....

[Posteritatis]

37. The kneejerk misanthropy wankfests articles like these always get is depressing. (nt)

[Xithras]

40. Virtually all of which will have atmospheres that will kill you in seconds.

The Earths atmosphere isn't the result of planetary development, but was created by the very life that lives on it. The odds of another planet having biological life that has followed an identical evolutionary pathway as Earth, which resulted in an atmosphere we can actually use, are virtually nil.

There probably are a handful of human habitable planets out there, but most will take millennia of terraforming, or will require any human settlers to permanently inhabit domes.

Remember, according to NASA, Venus is an "Earth like" planet that exists in our stars Goldilocks zone. Good luck moving in!

[FreeJoe]

43. Oh great...

8.8 billion planets to live on in a galaxy billions of years old and I get stuck in the same time period and country as Sarah Palin. What are the odds of that???

[napkinz]

44. And Ted Cruz!